Well, as someone who wrote 100 reviews in 107 days for my first 100 reviews and who is trying to publish 7 reviews per day this week for double points week - let me answer this question.
First of all - some of the people who have written hundreds of reviews - have been here for years
writing reviews. Laur3n has been reviewing for maybe 3 years now - which would be over 1000 days and has written a little over 600 reviews the last time I checked. That is not quite one per day. She might have been reviewing products longer than that - I'm not sure. But I know she's been reviewing a long time.
Now when you look at all the various categories of stuff you can review - anywhere from bath and body products to lingerie to dildos to vibrators to porn movies to books to candles to almost anything else...that's a lot of opportunities to review products. Some are going to be good - some are duds.
Now let me look at my own reviews. Since I have a template for my lingerie reviews - I can write one in about 2 hours. This includes the time it takes to take the photos, edit the photos, get the information on measurements and how to clean the garment, gather my thoughts on the item after wearing it around for a bit and trying to sit in it, lay down in it, possibly sleep in it, etc. I don't count my "trying on" time in that amount of time. I love lingerie - so I have a lot of it....hence a lot of stuff to review.
I used to be a book reviewer for a certain niche of products and I can whip out reviews fairly easily once I get my thoughts together. I'm also a full-time homemaker so I have plenty of time every day to work on reviews.
In addition, I've been married for 32 years now and my partner and I love to have sex on a very regular basis - sometimes daily. So it doesn't take us long to try out new toys and figure out if they work well for us and what are the good points and the bad points about them. Oftentimes after trying out a new product, we'll lay in bed and discuss how it worked, what my partner felt would have worked better, etc. etc. etc.
Anyway - I guess it's just a matter of time, having the chance to use the products a lot and having the ability to write come fairly naturally.
I love reviewing and I hope that when folks read my reviews, they can recognize that even though I write a lot of them and I write them fairly fast - I write quality reviews (or try to).